Western diets high in saturated fatty acids (SFA) are associated with increased risk of cardiovascular disease. Whilst diets rich in polyunsaturated fatty acids (PUFA) have been found to be cardio protective. Increasing evidence suggests that, at least in part cardiovascular disease may have its origin in utero, as a direct consequence of maternal dietary imbalance. Previously we have reported distinct effects of a SFA and PUFA maternal diets on offspring blood pressure at one year (LHS ref Br. J. Clin. Pharm). Systolic blood pressure in 1 year old offspring of PUFA fed dams were 20 mmHg lower than in the offspring of SFA fed dams The aim of the current study was to investigate vascular function in the adult offspring of dams fed either a SFA or PUFA diet during pregnancy. The two diets are representitative of typical western and Mediterranean diets. Sprague-Dawley rats were fed a diet supplemented with either SFA (Palm oil 20% w/w) or PUFA (Corn oil 20% w/w) for 10 days before, during pregnancy and suckling. After weaning all the offspring were fed a normal maintenance diet. Offspring were killed with an overdose of CO2 at 1 year of age. Third order branches of the mesenteric arteries were removed and mounted on a Mulvany-Halpern small vessel myograph. Constrictor function was assessed using noradrenaline (10-7 to 10-5 M), and the thromboxane analogue U46619 (10-8 to 10-6 M). Dilator function was assessed using acetylcholine (10-9 to 10-5 M) and nitric oxide (10-8 to 10-4). There was no significant difference in the endothelium-dependent relaxation to Acetylcholine [(% relaxation: PUFA 94.8±2.12 versus SFA 87.3±3.9; n=5); (EC50: PUFA-7.56±0.02 versus SFA-7.49±0.05)], endothelium-independent relaxation to NO (% relaxation: PUFA 92.8±3.01 versus SFA 91.1±1.2; n=5) or to the constrictors noradrenaline and U46619 in third order mesenteric arteries at 1 year. Values are given as the mean ± SEM and statistical significance determined using a students t-test (P<0.05). In summary, a high fat diet rich in PUFA compared to SFA during pregnancy and suckling permanently programs a blood pressure lowering effect in the adult offspring of PUFA fed dams compared to SFA fed dams. The vascular function in the same animals did not vary significantly between the groups indicating that the programming of blood pressure by maternal diet in this model is independent of small artery function.